Biomass and resource allocation patterns within the bulb of the perennial geophyte Haemanthus pubescens L. subsp. pubescens (Amaryllidaceae) in a periodic arid environment of lowland fynbos, South Africa

Biomass and resource allocation patterns in the constituent bulb parts of the geophytic species Haemanthus pubescens subsp. pubescens were studied in a seasonally periodic arid environment of lowland fynbos with oligotrophic soils. Concentration and allocation patterns of 10 resources were quantified. The species bulb parts (leaf-bases and stem-stock) allocate biomass and resources differentially. The study showed that the centrally located leafbases in the bulb preferentially accumulated > 50% of the total biomass and nutrients of the bulb. The juvenile and old leaf-bases contained < 50% of the biomass and nutrient bulk. Some of the nutrients (P, K and Mg) showed constant concentrations in the leaf-bases and stem-stock as did water. N, soluble carbohydrates and starch exhibited decreased concentrations with age and Zn, Mn, Fe, Cu, Ca and Na showed increased concentrations with age. The allocation patterns of the nutrients in the bulb components indicate that they are largely used for carbohydrate and water storage.